Scanning using beams of electromagnetic radiation is used in a myriad of present day technologies; from 3D environment scanning to spectrography to microscopy. As such, an efficient method, apparatus and system are needed to accelerate the process. Prior art teaches the use of one or a few beams to scan an environment and can determine environmental information based on the reflected beam. To efficiently operate the beam, or beams, to scan the environment, a constant propagation angle may need to be maintained, while still traversing a 2D grid.
Many current technologies use a single or only a few focal points to scan 3D areas. Specifically, conventional confocal microscopy raster scans a single focal point to generate 3D information. To improve data acquisition speed, an multiplexing array of foci can be used.
A typical example of a multiplexing scheme is the Yokogawa spinning disk confocal method where an array of microlenslets on a rotating disk covers the full field of view. The present technology for beam scanning usually employs galvanometric mirrors in a way to alter the angle of the beam. It does this to scan a 2D (x and y) grid. However, given the nature of a galvanometric mirror, this method only works with one or a few beams. If one were to introduce a larger array of beams to accelerate the process, as is commonly done in multiplexing confocal microscopy, the galvanometric mirror will not treat all the beams uniformly and descan are not disclosed in prior art. As the galvanometric mirrors oscillate across an angle, different beams will scan out different ranges of the sample. Therefore, if one beam is aligned to scan a specific region, then other beams on the periphery will potentially behave differently and scan too small or too large of a region; leaving parts of the sample scanned multiple times, while other parts are not scanned at all. The galvo window setup is another method that is disclosed in prior art; however its use is limited to laser machining, and the benefits of multiplexing and descan are not explored.
Alternatively, a prism is also presently used in the art to accomplish a similar goal to the galvanometric mirror. Rotating a prism can predictably refract beams, but incur the same issues as the galvanometric mirror in that if an array of beams were to be used, all beams would not be refracted equally.
Another option is translation stages which can also be used to move mirrors forward and backward to change the deflection of a beam while maintaining a constant propagation angle. However, translation stages generally do not offer a good combination of speed, resolution, and mass supported. The fastest and most accurate stages are piezoelectric stages, but these have very low load capacities and travel ranges.